JP2000292009A - Heat storing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storing device to prevent leakage of a heat storing material to an external part. SOLUTION: A heat storing device 11 comprises a container body 12 the internal part of which is filled with a heat storing material 16; a heater 18 to heat the heat storing material 16; and a heat transfer pipe 17 through which a heating medium flows and which is disposed in the container body 12 and which performs heat-exchange between the heat storing material 16 and the heating medium. The heat transfer pipe 17 and the heater 18 are led out to an external part through the upper surface, making no contact with the heat storing material 16, of the container body 12. Thereby, the heat transfer pipe 17 and the heater 18 eliminate a need to extend through the heat storing material filling part of the container body 12. This constitution prevents leakage of the molten heat storing material 16 from a through-part U to the external part of the container body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage device that stores heat in a substance having a large specific heat and uses the sensible heat later.

[0002]

2. Description of the Related Art As shown in FIG. 4, a heat transfer tube 53 and a heater 54 are provided in an inner case 52 of a heat storage device 51, and a heat storage material 55 is filled. Inner case 5
2 is housed in an outer case 57 with its entire surface covered with a heat insulating material 56. Heat transfer tube 53 and heater 54
Are led out through the inner case 52, the heat insulating material 56 and the outer case 57.

When the heater 54 is energized and heated, the heat storage material 55 is heated and stores heat. In this state, when water is supplied from one of the heat transfer tubes 53, the water is heated by the heat of the heat storage material 55, and is spouted from the other of the heat transfer tubes 53 as steam. In this way, the heat stored in the heat storage material 55 is taken out.

[0004]

However, in the heat storage device 51, the heat transfer tube 53 penetrates from the portion of the inner case 52 filled with the heat storage material 55 to the outside, and is fixed by welding at this penetrating portion. For this reason, when the heater 54 is energized and heated, and the heat storage material 55 is heated to a high temperature, cracks are generated in the welded portion 58 due to thermal fatigue or the like if there is a welding defect, and the heat storage material 55 melted from the weld portion 58 becomes external. There was a risk of leakage.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat storage device that can prevent a heat storage material from leaking outside.

[0006]

According to the first aspect of the present invention, there is provided a container body filled with a heat storage material, a heating means for heating the heat storage material, a heat medium flowing inside, and a container body. Heat exchange means for exchanging heat between the heat storage material and the heat medium, wherein the heating means and the heat exchange means are provided outside through a top wall which is not in contact with the heat storage material of the container body. The gist is that it is provided so as to be derived.

According to a second aspect of the present invention, in the first aspect of the present invention, a marginal space is formed between the upper surface of the heat storage material whose volume has expanded and the upper surface wall of the container body. That is the gist.

According to a third aspect of the present invention, in the first or second aspect of the invention, the container main body has a heat storage container having an opening at an upper part, and a lid for closing the opening. The gist of the present invention is that a joint surface between the lid and the heat storage container is provided above the highest upper surface of the heat storage material whose volume has been expanded.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a reverse flow of the heat medium is provided midway on the heat medium supply side of the heat exchange means. The gist of the invention is to provide a backflow prevention means for preventing the backflow. (Operation) Therefore, in the first aspect of the present invention, the heating means and the heat exchange means are led out to the outside via the upper wall which does not contact the heat storage material filled in the container body. Therefore, it is not necessary for the heating means and the heat exchange means to penetrate the heat storage material-filled portion of the container body. Therefore, leakage of the molten heat storage material from the penetrating portion to the outside of the container body is prevented.

[0010] According to the second aspect of the present invention, in addition to the function of the first aspect of the present invention, a surplus gap is formed between the upper surface of the volumetrically expanded molten heat storage material and the upper surface wall of the container body. Is done. Therefore, when the heat storage material is melted, the heat storage material does not come into contact with the upper wall of the container body. Therefore, leakage of the molten heat storage material from the through portion (weld portion) of the upper wall of the container body to the outside is prevented.

According to the third aspect of the present invention, in addition to the operation of the first or second aspect, when the heat storage material is melted, the heat storage material does not reach the joining surface of the container body. Leakage of the molten heat storage material to the outside of the container body is prevented.

[0012] In the invention described in claim 4, in addition to the function of the invention described in any one of claims 1 to 3, the heat medium is heated by the heat of the heat storage material to form steam. As a result, backflow (rising) in the heat exchange means is prevented. For this reason, the heat medium flows smoothly from the heat medium supply side of the heat exchange means to the steam ejection side.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment in which the present invention is embodied in a heat storage device will be described below with reference to FIGS.

As shown in FIG. 1 and FIG.
Is formed in a double wall structure composed of an inner case 13 as an inner wall made of stainless steel and an outer case 14 as an outer wall. The inner case 13 is housed in the outer case 14 with the entire surface covered with a heat insulating material 15 such as calcium silicate as a heat insulating means.

A heat storage material 16 for storing heat is filled in the inner case 13, and a predetermined gap T is provided between the upper surface of the heat storage material 16 and the inner case 13. The heat storage material 16 is composed of solid magnesia (magnesium oxide) and a nitrate (a mixture of sodium nitrate, sodium nitrite, potassium nitrate, etc.) that liquefies in the heat storage temperature range. When the nitrate is melted (liquefied), the volume slightly expands (in the present embodiment, expands by about 13%).

A heat transfer tube 17 as a heat exchange means is spirally disposed in the inner case 13. In the inner case 13, a heater 18 as a heating means is disposed in a U-shape. Both ends of the heat transfer tube 17 and the heater 18 pass through upper surface walls 13a and 14a of both cases 13 and 14 via a sleeve 19 made of stainless steel, respectively, and are led out. The heat transfer tube 17 and the heater 18 are fixed to the penetrating portions U of the cases 13 and 14 by welding.

The space T is set to have a capacity that allows volume expansion accompanying melting of the nitrate. That is, as shown by a two-dot chain line in FIG. 1, even if the heat storage material 16 expands in volume, a surplus gap Ta is formed between the upper surface of the heat storage material 16 and the inner case 13. ing. Therefore, the upper surface of the melted heat storage material 16 does not reach the penetrating portion U of the inner case 13.

A check valve 20 as a backflow preventing means for preventing a backflow of the heat medium (water) is provided outside the vessel body 12 on the heat medium supply side (inlet side) of the heat transfer tube 17. Is provided.

The inner and outer cases 13 and 14 function as wall materials for shutting off the heat storage material 16 from the outside air. The upper walls 13a, 14a of both cases 13, 14
The upper surface wall J of the container body 12 is formed from.

Next, the heat storage device 1 configured as described above
1 will be described. When the heater 18 is energized and heated, the heat storage material 16 is heated to store heat. Then, when the heat storage material 16 reaches a predetermined heat storage temperature (about 450 ° C. in the present embodiment), the nitrate is melted, the gap between the magnesia, the gap between the magnesia and the heat transfer tube 17, and the gap between the magnesia and the heater 18. Is filled. Therefore, the heat storage amount of the heat storage material 16 increases.

Further, the volume expansion accompanying the melting of the nitrate is allowed by the gap T between the upper surface of the heat storage material 16 and the inner case 13. That is, when the nitrate is melted, an extra space Ta is formed between the upper surface of the heat storage material 16 and the inner case 13.
For this reason, the heat storage material 16 does not contact the penetrating portion U of the inner case 13. Therefore, even if there is poor welding or the like in the penetrating portion U or cracks or the like occur in the welded portion due to thermal fatigue or the like due to heating, the molten nitrate does not leak out from the welded portion.

Although the heat stored in the heat storage material 16 is conducted to the inner case 13, the heat insulating material 15 is interposed between the inner case 13 and the outer case 14 so that the heat is transferred from the inner case 13 to the outer case. Heat conduction to the case 14 is suppressed. Therefore, the heat stored in the heat storage material 16 is maintained.

In this state, a pump (not shown) provided on the heat medium supply side (inlet side) of the heat transfer tube 17 is driven,
When water is supplied as a heat medium, the water is heated by the heat stored in the heat storage material 16 via the heat transfer tube 17 and turns into steam. In the heat transfer tube 17, the backflow (rising) of the steam to the heat medium supply side is prevented by the check valve 20, and the steam is ejected from the steam ejection side (exit side) of the heat transfer tube 17. In this way, the heat stored in the heat storage material 16 is extracted to the outside.

Therefore, according to the present embodiment, the following effects can be obtained. The heat transfer tube 17 and the heater 18 are configured to be led out through the upper wall J that does not contact the heat storage material 16 in the container body 12. Therefore, the heat transfer tube 17 and the heater 1
8 does not need to penetrate the heat storage material 16 filling portion of the container body 12. That is, even if a crack occurs in the penetrating portion (welded portion) U due to poor welding or the like, the heat storage material 16 does not contact the penetrating portion U, so that the heat storage material 16 can be prevented from leaking to the outside. it can.

An air gap T is provided between the upper surface of the heat storage material 16 and the upper surface wall of the container body 12 to allow volume expansion accompanying the melting of the heat storage material 16. For this reason, the volume expansion accompanying the melting of the heat storage material 16 is allowed by the gap T,
The increase in the internal pressure of the container body 12 due to the volume expansion of is reduced.

The space T is configured such that a surplus space Ta is formed between the upper surface of the volumetrically expanded molten heat storage material 16 and the upper surface wall J of the container body 12. Therefore, when the heat storage material 16 is melted, the heat storage material 16 does not come into contact with the upper wall J. Therefore, it is possible to prevent the melted heat storage material 16 from leaking from the through portion (weld portion) U of the upper surface wall J to the outside.

In the middle of the heat transfer tube 17 on the heat medium supply side, a check valve 20 for preventing a back flow of the heat medium (water) is provided. Therefore, the reverse flow of the water supplied from the heat medium supply side of the heat transfer tube 17 is prevented by the check valve 20. Therefore, water can flow smoothly from the heat medium supply side of the heat transfer tube 17 to the steam ejection side. (Second Embodiment) Next, a second embodiment will be described with reference to FIG. The present embodiment differs from the first embodiment in that the container body 12 is divided into a heat storage container 32 and a lid 34, which will be described later, and that the heat storage material 16 is insulated by vacuum insulation. Therefore, the same members as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 3, the heat storage device 31 is provided with a cylindrical heat storage container 32 having an open top and a bottom, and a lid 34 for closing an opening 33 of the container 32.
The heat storage container 32 has a bottomed cylindrical inner wall 32a and an outer wall 32b.
It is formed in a double wall structure consisting of both walls 32a, 32
A space S1 is formed between 2b.

The two walls 32a, 32b are formed by drawing using a press, and flange-shaped flange portions 35a, 35b are formed at the periphery of each upper opening. And, both walls 32a, 32b are flange portions 35a,
By welding all over the circumference of 35b, it is mutually fixed and the airtightness of the space S1 is ensured.

The lid 34 has a double-walled structure consisting of an inner wall 34a and an outer wall 34b formed in a closed cylindrical shape, and a space S2 is formed between the two walls 34a and 34b. The two walls 34a, 34b are fixed to each other by welding over the entire periphery of the flanges 36a, 36b at the periphery of the opening, and the airtightness of the space S2 is ensured.

The spaces S1, S of the heat storage container 32 and the lid 34
Reference numeral 2 denotes a vacuum, and the pressure of the air in both spaces S1 and S2 is set to be 1 Torr or less. In this specification, a vacuum refers to a state in a space filled with a gas (air in the present embodiment) at a pressure lower than the normal atmospheric pressure, where the absolute vacuum is 0 Torr and the atmospheric pressure is 760.
Torr.

The opening 33 of the heat storage container 32 has a lid 34.
The lid 34 is fixed to the heat storage container 32. A heat insulating material 38 such as calcium silicate is interposed between the upper surface of the heat storage container 32 and the lid 34 (joining surface), thereby preventing heat transfer between the heat storage container 32 and the lid 34. . Further, the heat storage material 16 is stored in the heat storage container 32.
Is filled, and the upper surface of the heat storage material 16 and the heat storage container 32
A predetermined space T is provided between the upper end surface and the upper end surface.

A heat transfer tube 17 and a heater 18 are disposed in the heat storage container 32. Both ends of the heat transfer tube 32 pass through the inner and outer walls 34a, 34b of the lid 34 via the sleeve 19 in an airtight manner. Is derived. Heat transfer tube 17 and heater 18 are welded at penetrating portion V of lid 34. In the middle of the heat transfer tube 17 on the side of the heat medium (water) supply, a check valve 20 is provided.

The space T is set so as to have a capacity to allow volume expansion accompanying melting of the nitrate. That is, as shown by the two-dot chain line in FIG. 3, even if the heat storage material 16 expands in volume, a marginal space Ta is formed between the upper surface of the heat storage material 16 and the upper end surface of the heat storage container 32. Is configured. Therefore, even if the melted heat storage material 16 expands, its upper surface does not reach the upper end surface of the heat storage container 32.
Further, the heat storage material 16 does not reach the penetrating portion V of the lid 34.

The heat storage container 32 and the lid 34 constitute a container body L. The lid 34 functions as an upper wall of the container body L. The inner walls 32a and 34a and the outer walls 32b and 34b of the heat storage container 32 and the lid 34
It functions as a wall material for shutting off between 6 and the outside air.

Next, the heat storage device 3 configured as described above
1 will be described. Since the spaces S1 and S2 are vacuum (1 Torr or less), both spaces S1 and S2
The convection of air in S1 and S2 is almost negligible, and heat conduction from the inner wall 32a to the outer wall 32b due to the convection is hindered.
That is, the heat stored in the heat storage material 16 is prevented from being transferred to the outside via the outer wall 32b, and the heat stored in the heat storage material 16 is maintained.

The volume expansion accompanying the melting of the nitrate is caused by the heat storage material 1
6 is allowed by the space T between the upper surface of the heat storage container 32 and the upper surface of the heat storage container 32. That is, when the nitrate is melted, a surplus gap Ta is formed between the upper surface of the heat storage material 16 and the upper end surface of the heat storage container 32. Therefore, the heat storage material 16 does not leak outside through the penetrating portion V of the lid 34.

Further, the inner and outer walls 32a, 32b are formed with flange portions 35a, 3 protruding outward at the upper ends of the respective outer peripheries.
At 5b, they are fixed to each other by welding. Therefore, the heat storage material 1 filled in the heat storage container 32 (the inner case 13)
6 does not come into contact with the welded portions of the flange portions 35a, 35b.

Therefore, even if the flange portions 35a, 35b and the penetrating portion V have defective welding or the like, and cracks or the like occur in the welded portion due to thermal fatigue due to heating, the molten nitrate leaks from the welded portion to the outside. I will not do it.

In the heat transfer tube 17, the backflow (rising) of the steam to the heat medium supply side is prevented by the check valve 20. Therefore, according to the present embodiment, the following effects can be obtained.

The heat transfer tube 17 and the heater 18 are configured to penetrate the lid 34 through the opening 33 of the heat storage container 32 and to be led out to the outside. Therefore, it is not necessary for the heat transfer tube 17 and the heater 18 to penetrate through the heat storage material 32 of the heat storage container 32. That is, even if a crack occurs in the penetrating portion (welded portion) V due to poor welding or the like, the heat storage material 16 does not contact the penetrating portion V, so that the heat storage material 16 can be prevented from leaking to the outside. .

A gap T is provided between the upper surface of the heat storage material 16 and the upper end surface (lid 34) of the heat storage container 32 to allow volume expansion accompanying the melting of the heat storage material 16. In addition, the capacity of the gap T was set such that a surplus gap Ta was formed between the upper surface of the heat storage material 16 whose volume had expanded and the upper surface of the heat storage container 32. For this reason, the volume expansion accompanying the melting of the heat storage material 16 is allowed by the gap T, and does not exceed the upper surface of the heat storage container 32 even if the volume of the heat storage material 16 expands. Therefore, it is possible to prevent the molten heat storage material 16 from leaking from the penetrating portion V to the outside.

The container body L of the heat storage device 31 is composed of a heat storage container 32 having an opening 33 at an upper part, and a lid 34 for closing the opening 33. For this reason, the opening of the heat storage container is closed by the lid, and there is no particular need for welding or the like. Therefore, the assembly of the heat storage device is simplified.

The heat storage container 32 and the lid 34 have a double wall structure including inner walls 32a, 34a and outer walls 32b, 34b, respectively. The inner walls 32a, 34a and the outer walls 32b, 3
The spaces S1 and S2 formed between the space 4b and the space 4b were evacuated.
For this reason, the space S1 due to the heat stored in the heat storage material 16
The convection of the air in S2 is suppressed by the vacuum. Therefore,
The heat stored in the heat storage material 16 can be held efficiently.

Space S between the heat storage container 32 and the lid 34
The heat storage material 16 was configured to be thermally insulated by evacuating 1 and S2. The inner and outer walls 32 of the heat storage container 32
a and 32b were formed by pressing a stainless steel plate. For this reason, the operation | work which covers the heat storage container 32 and the cover 34 with the heat insulating material 15 (refer FIG. 1) etc. can be made unnecessary, and the heat storage container 32 can be easily formed.

The above embodiment may be modified as follows. In the first embodiment, the heat insulating material 15 is omitted,
The space between the inner and outer cases 13 and 14 occupied by the heat insulating material 15 may be evacuated (for example, 1 Torr or less). In this way, the operation of covering the inner case 13 with the heat insulating material 15 (see FIG. 1) can be omitted, and the manufacturing efficiency of the heat storage device 11 can be improved.

In the second embodiment, the space S
1, a solid heat insulating material (not shown) for reinforcement may be arranged in S2. With this configuration, when the spaces S1 and S2 are evacuated to vacuum, the inner and outer walls 32a, 34a, 32b, and 34b can be prevented from denting to the vacuum side due to a negative pressure in the spaces S1 and S2.

In the first and second embodiments,
The heat transfer tube 17 and the heater 18 may be fixed to the container body 12, L with bolts and nuts. Even if you do this,
The heat transfer tube 17 and the heater 18 can be fixed to the container body 12, L. In the second embodiment, the space S
2 must be kept airtight.

Next, technical ideas other than the claimed invention which can be grasped from the embodiment will be described below together with their effects. The heat storage device according to claim 3, wherein the heat insulating means is configured to cover the entire periphery of the wall material with a solid heat insulating material. With this configuration, the heat storage material is insulated only by covering the entire periphery of the wall material with the heat insulating material, so that the configuration of the heat storage device can be simplified.

The heat storage device according to claim 3, wherein the heat insulating means has a multi-wall structure including at least an inner wall and an outer wall, and a closed space formed between the inner and outer walls is evacuated. With this configuration, heat insulation is performed by evacuating the sealed space formed between the inner and outer walls, so that it is not necessary to cover the entire surface of the wall material with a heat insulating material or the like.

The heat storage device according to claim 5, wherein the inner and outer walls are formed into a predetermined shape by press working. In this way, the inner and outer walls can be easily formed.

[0052]

According to the first aspect of the present invention, it is not necessary for the heating means and the heat exchange means to penetrate the heat storage material-filled portion of the container body, and the molten heat storage material flows out of the container body from the penetrated portion. Leakage can be prevented.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention described in the above, even if the heat storage material expands in volume, the heat storage material does not contact the upper wall of the container body, thereby preventing the molten heat storage material from leaking out of the container body due to volume expansion. be able to.

According to the invention described in claim 3, according to claim 1
Alternatively, in addition to the effect of the invention described in claim 2, when the heat storage material is melted, the heat storage material does not reach the joint surface of the container main body, and leakage of the molten heat storage material to the outside of the container main body can be prevented. .

According to the fourth aspect of the present invention, the first aspect is provided.
In addition to the effects of the invention described in any one of the third to third aspects, the heat medium can flow smoothly from the inlet side to the outlet side of the heat exchange means.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a heat storage device according to a first embodiment.

FIG. 2 is a sectional view taken along line 1-1 in FIG. 1;

FIG. 3 is a front sectional view of a heat storage device according to a second embodiment.

FIG. 4 is a front sectional view of a conventional heat storage device.

[Explanation of symbols]

11, 31: heat storage device, 12: container body, 13: inner case (inner wall), 14: outer case (outer wall), 15: heat insulator (insulation means), 16: heat storage material, 17: heat transfer tube (heat exchange means) ), 18: heater (heating means), 20: check valve (backflow prevention means), 32: heat storage container, 32a: inner wall of 32,
32b 32 outer wall, 33 opening, 34 lid, 34
a ... 34 inner wall, 34b ... 34 outer wall, S1, S2 ... closed space (insulation means), J ... 12 upper surface wall, L ... container body, T ... gap, Ta ... room gap, U, V ... penetration part .

Claims (4)

[Claims] 1. A container body filled with a heat storage material, a heating means for heating the heat storage material, a heat medium flowing inside, and disposed inside the container body, the heat storage material and the heat medium A heat storage device, comprising: heat exchange means for performing heat exchange between the heat storage means, and the heating means and the heat exchange means provided so as to be led out to the outside via an upper wall not in contact with the heat storage material of the container body. 2. The heat storage device according to claim 1, wherein a marginal gap is formed between the upper surface of the heat storage material whose volume has expanded and the upper surface wall of the container body. 3. The container main body comprises a heat storage container having an opening at an upper part thereof, and a lid for closing the opening, and the container main body is provided above the highest surface of the heat storage material whose volume has expanded. The heat storage device according to claim 1 or 2, wherein a joint surface between the lid and the heat storage container is provided. 4. The heat exchanger according to claim 1, further comprising a backflow preventing means provided on a heat medium supply side of the heat exchange means for preventing a backflow of the heat medium. Heat storage device.